Turbine engine systems require careful design and control to provide satisfactory performance. In addition, governmental and industrial regulations impose limitations on turbine engine emissions. As a result, the operational parameters of turbine engine systems are closely monitored and controlled to meet the regulatory requirements.
U.S. Application Publication No. 2011/0126547 A1 to Nanataki et al. discloses a twin-shaft gas turbine engine system configured to selectively operate in a first control mode and a second control mode. In the first control mode, an inlet guide vane angle in a compressor of the system is controlled in accordance with a corrected shaft rotation speed. The corrected shaft rotation speed is obtained by normalizing an actual shaft speed value with an atmospheric temperature value. In the second control mode, the inlet guide vane angle is controlled to maintain a constant gas generator shaft rotation speed. The first control mode is used to start, stop, and operate the turbine engine system under fixed or lower load conditions, while the second control mode is used under other operational conditions.